Enzymes

-Metabolism: describes chemical reactions occurring constantly to achieve homeostasis
Metabolic pathways: order of chemical reactions from initial reactants to final proteins Step 1  Step 2  Step 3 …  Protein *Each step requires a different enzyme *Produces complex molecules
-Enzymes: protein that speeds up a reaction without being consumed
Sites of reaction are not changed or used up during/after a reaction
Highly specific
Suffix –ase E + S  ES  E + P

-Lock & Key theory: FALSE
E & S meet and fit perfectly with the enzyme
Inaccurate
-Induced fit theory
What we use today, more accurate
Enzyme is not rigid: slightly changes shape when it binds to substrate to get a better grip
Enzyme returns to its original shape after the reaction
-How do enzymes work?
Lower activation energy required for a reaction to occur
Activation energy: energy that must be supplied to cause molecules to react with each other

Enzymes do this by bringing the substrate molecules together and holding them in place long enough for the reaction to take place
-What are enzymes made of?
Protein part called apoenzyme
Non-protein part called coenzyme

-5 factors affecting enzyme activity:

1. pH
Most enzymes prefer pH’s of 6-8
If pH is too high, enzyme denatures
2. Temperature
Decreasing the temperature will decrease the rate of reaction
Increasing the temperature will at first speed up the reaction, but temperatures too high (above 45 degrees) will denature the enzyme
3. Concentration of substrates
[ ] means concentration
If [ ] increases, amount of product/rate of reaction increases
After certain [ ], rate won’t increase any more because all enzymes are ‘saturated’ with substrates and can’t work any faster
4. Concentration of